Safety Boot with Protective Layer

ABSTRACT

Safety footwear manufactured in a foamed plastic material with an additional protective outer layer, and having three-dimensionally shaped inserts provided therein is disclosed. The protective outer layer provides the safety footwear with improved cleanliness and durability, enabling it to be used in extreme environments. A method for manufacturing the footwear is also disclosed.

FIELD OF THE INVENTION

The present invention concerns footwear manufactured in a foamed plasticmaterial with an additional protective outer layer, and having3-dimensionally shaped inserts provided therein or thereon, inparticular the invention concerns safety boots having a reinforcementinsert in the toe-section.

BACKGROUND OF THE INVENTION

Safety boots are wide-spread in industrial environments from slaughterhouses and food auction halls to food preparation and food packagingplants. Furthermore they are used in industries where extremeenvironmental conditions are present, for example freezers (extremecold) and chemical plants.

U.S. Pat. No. 5,163,198 discloses a safety boot having a shaft of foamedplastic material and a steel toe cap partially embedded therein. Adrawback of a safety boot according to U.S. '198 however is that theouter surface of the boot shaft, consisting of a foamed material haspoor cleanliness, and small cavities wherein small particles settle thatare very difficult to remove.

Especially since several food crises spreading rapidly geographicallyand infecting large numbers of food stocks and or people have occurredregularly in the last decade, cleanliness of the footwear has become animportant attention point in food processing areas.

In order to address the above problem WO 00/51458 discloses bootscomprising a foamed EVA-based shaft covered at its outer surface with athermoplastic polyurethane based liner. According to WO 00/51458 theboots are manufactured by manufacturing a composite sheet comprising afoamed EVA layer and a TPU liner, subsequently heating said compositesheet and compression molding the heated sheet to form the upper sectionof a boot.

Although the technology disclosed in WO 00/51458 allows manufacturing ofboots having a surface with a low roughness that is easy to clean, thedisclosed method does not allow manufacturing safety boots having a3-dimensionally shaped insert for the reason that such insert cannot beincorporated in a composite sheet for subsequent compression molding.

It is clear from the above that there remains a market demand for easyto clean and maintain safety boots.

SUMMARY OF THE INVENTION

The present invention addresses this problem by providing a footwearhaving an upper section of foamed plastic material and a liner ofplastic material covering the outer surface of said upper section,characterized in that the upper section further comprises a3-dimensionally pre-shaped insert.

The present invention also concerns a method for manufacturing suchfootwear, said method comprising the steps of:

-   a. Providing a mold;-   b. Providing a 3-dimensionally shaped material in the mold cavity;-   c. Providing a liner in the mold cavity;-   d. Immobilizing said liner to the inner surface of the mold cavity;-   e. Subsequently injecting and foaming a foamable plastic material in    said mold cavity to manufacture the footwear.

BRIEF DESCRIPTION OF THE INVENTION

The present invention describes safety footwear more specifically a bootand a method of producing such a boot. The boot comprises of severallayers of material each having their specific function and properties.

According to the present invention the safety footwear comprise3-dimensional inserts which are preferably embedded entirely in the foamlayer of the toe section of the footwear. These preformed inserts aremade from a rigid material i.e. metal (steel), polyethylenepolypropylene, polycarbonate, reinforced glass fibers or the like. Insome cases perforations might be present in the inserts.

The method results in the construction of comfortable safety footwearhaving the properties necessary for use in extreme conditions. Moreover,the methods of the present invention provide the flexibility to vary theproperties of the resultant footwear, allowing the footwear to bespecifically tailored to the environment in which it is designed to beused, without the need for multiple sets of molds or manufacturingequipment.

The liner, preferably thermoplastic polyurethane, is connected to thefoam layer during the 3-dimensional shaping of the footwear without anyuse of glue or any other mechanical fastening means. This method hasgreat advantage towards the ease of manufacturing and it also lowers thecost. The liner also avoids that dirt, sand, micro-organisms or anyparticles can settle in the boot. Furthermore the liner makes the bootmore durable.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 represents different kind of footwear including the safety insert

DETAILED DESCRIPTION OF THE INVENTION

The present invention comprises footwear, more particularly a safetyboot and a method of manufacturing safety footwear. The boot comprises asole and an upper section fixed to said sole. According to the presentinvention the upper section is a layered structure comprising a foamlayer and a liner on the outer surface of said foam layer. The solesection can be manufactured from rubber, polymer or any other suitablematerial.

The term boot includes any kind of safety footwear shown in FIG. 1 froma low shoe A to an ankle boot B and from a half-knee boot C, knee-heightboot D to a thigh boot E. All these kind of boots are shown in ISO20345.Typical examples are Wellington® boots.

It is preferable that one or more of the layers forming the uppersection of the footwear include a thermo-formable material. In onepreferred embodiment, the footwear in particular a boot comprises atleast a first layer of thermoset foam and a second layer (liner) ofthermoplastic foil.

The term upper section refers to the entire boot section without sole.Other terms which are used for this part are vamp or upper.

At least one 3-dimensionally shaped insert is provided in said foamlayer, either partially, more preferably entirely embedded in the foamlayer. By partially embedded is meant that at least 50% of the surfaceof the rigid toe cap, preferably 70%, highly preferred 90% is embeddedin the foam layer. These inserts can be made of any kind of metal, orpolymer material. The said inserts meet with the international standardslike EN/ISO 20345, EN12568, ASTM S2413 and CAN/CSA Z195, regardless theissue. The said inserts are capable to withstand an impact force rangingfrom 100 J to 200 J and a compression force of at least 10000N,preferably 15000N. The foam layer preferably comprises a thermoset foam,preferably polyurethane.

In a preferred embodiment the inserts are positioned in the toe sectionof the boot. The said insert comprises a rigid toe cap, providing animpact and compression resistant safety boot.

In another preferred embodiment the inserts are perforated resulting inan even better bonding of rigid insert and the foam layer.

The liner can be any kind of material, depending on the desiredproperties of the footwear being constructed. The liner preferablycomprises thermoplastic polyurethane (TPU). The thickness, hardness,density, roughness, durability or color, etc. of the thermoplastic foilcan be varied according to the function. The foil also improves thecleanliness.

A third layer of fabric can be positioned on the inner side. Suitablefabrics can include a mesh fabric formed from nylon, polyester,poly-cotton, cotton, acetate, or acrylic.

The present invention also concerns a method of producing such footwearby molding and includes the steps of positioning the thermoplastic foilin a mold member having a mold cavity. Hereby it is important the lineris fixed firmly in the mold. This provides a smooth surface whereon thefoamable material can be applied.

In the next step the rigid toe cap is placed in the toe section of thefootwear in the mold. After the positioning of the toe cap, the mold isclosed and the foamable plastic material is injected into the mold. Thefoaming reaction can take place before or after injection. By thismethod of forming, the rigid toe cap is entirely or partially embeddedin the foam layer. This has the advantage of making the boot moreflexible and thus improving the comfort of the wearer.

Using this method the upper section of the footwear is formed to thedesired 3-dimensional shape.

The resulting upper section can be joined to a sole, as well as otherfootwear components, to complete the construction of the safety boot.

In a preferred embodiment the sole is added to the upper section afterthe forming of the upper section. This is achieved by introducing anadditional cavity onto the upper section. Subsequently the additionalcavity is closed and sole material is injected. This method ofmanufacturing a boot allows a strong bonding between the upper sectionand the sole section without using any adhesives or other methods suchas sewing.

The manufacturing method of the present invention simplifies safetyfootwear construction, reducing manufacturing costs and increasing theprocess flexibility, providing a very good outside barrier which canprotect the foam from staining. While providing a better outsidebarrier, the foam can be made lighter thus saving material costs whichcould not be achieved without the foil.

1. Footwear having an upper section of foamed plastic material and aliner of plastic material covering the outer surface of said uppersection, characterized in that the upper section further comprises athree-dimensionally shaped insert.
 2. The footwear according to claim 1,wherein said insert is at least partially embedded in said foamedmaterial, more preferably entirely embedded in said foamed material. 3.The footwear according to claim 2, wherein said insert is a safety cap,positioned in the toe-section of the footwear.
 4. The footwear accordingto claim 3, wherein the foamed material contacts said liner and whereinno glue or mechanical fastening means is applied between the foamedmaterial and the liner.
 5. The footwear according to claim 4, whereinsaid insert resists an impact force of at least 100 joules and acompression force of at least 10000N.
 6. The footwear according to claim5, wherein said insert is manufactured in a material chosen from thegroup consisting of metal, in particular steel, polyethylene,polypropylene, polycarbonate and reinforced glass fibers.
 7. Thefootwear according to claim 6, wherein said foamed material is apolyurethane based foam material.
 8. The footwear according to claim 7,wherein said liner is composed of a polyurethane based material,preferably a thermoplastic polyurethane based material.
 9. The footwearaccording to claim 8, wherein said footwear is a low shoe, ankle boot,half-knee boot, knee-height boot, thigh boot.
 10. A method ofmanufacturing footwear as identified in claim 1, said method comprisingthe steps of: providing a mold; providing a three-dimensionally shapedmaterial in the mold cavity; a liner in the mold cavity; immobilizingsaid liner to the inner surface of the mold cavity; and subsequentlyinjecting and foaming a foamable plastic material in said mold cavity tomanufacture the footwear.
 11. The method according to claim 10, whereinsaid foamable plastic is injected and foamed directly against saidliner.
 12. The footwear according to claim 1, wherein said insert is asafety cap, positioned in the toe-section of the footwear.
 13. Thefootwear according to claim 1, wherein the foamed material contacts saidliner and wherein no glue or mechanical fastening means is appliedbetween the foamed material and the liner.
 14. The footwear according toclaim 1, wherein said insert resists an impact force of at least 100joules and a compression force of at least 10000N.
 15. The footwearaccording to claim 1, wherein said insert is manufactured in a materialchosen from the group consisting of metal, in particular steel,polyethylene, polypropylene, polycarbonate and reinforced glass fibers.16. The footwear according to claim 1, wherein said foamed material is apolyurethane based foam material.
 17. The footwear according to claim 1,wherein said liner is composed of a polyurethane based material,preferably a thermoplastic polyurethane based material.
 18. The footwearaccording to claim 1, wherein said footwear is a low shoe, ankle boot,half-knee boot, knee-height boot, thigh boot.